Characterization of bZip-Type Transcription Factor AtfA with Reference to Stress Responses of Conidia of<i>Aspergillus nidulans</i>

Hagiwara, Daisuke; Asano, Yoshihiro; Yamashino, Takafumi; Mizuno, Takeshi

doi:10.1271/bbb.80001

Cited by 66 publications

(112 citation statements)

References 18 publications

(36 reference statements)

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“…However, no obvious role for this protein was observed in canonical stress responses, in contrast to those reported for other Yap-like bZIPs including those of Aspergillus species Hagiwara et al, 2008;Reverberi et al, 2012;Sakamoto et al, 2009). We hypothesized that Yap-like bZIPs might preferentially govern different defensive responses in A. nidulans, and thus created a series of deletion and overexpression strains of a subset of Yap-like bZIPs to examine this hypothesis.…”

Section: Discussionmentioning

confidence: 55%

“…To estimate the stress sensitivity of the mutants, 10 5 freshly grown (6 days) conidia washed and suspended in 5 ml 0.9 % NaCl, 0.01 % Tween 80 (Eigentler et al, 2012) were spotted on minimal-nitrate medium agar plates (Balázs et al, 2010;Hagiwara et al, 2007Hagiwara et al, , 2008, which were also supplemented with one of the following stress-generating agents (concentrations and mechanisms of actions are given in parentheses): diamide (2 mmol l 21 , triggers glutathione redox imbalance), menadione sodium bisulphite (MSB; 0.12 mmol l 21 , increases intracellular superoxide concentrations), tert-butylhydroperoxide (tBOOH; 0.8 mmol l 21 , accelerates lipid peroxidation) and H 2 O 2 (6.0 mmol l 21 , increases intracellular peroxide concentrations). The surface cultures of RWY17.3 (OE : : napA), RWY18.4 (OE : : zipA) and RWY19.1 (OE : : zipB) were always supplemented with pyridoxine at a concentration of 200 mg l…”

Section: W-b Yin and Othersmentioning

confidence: 99%

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bZIP transcription factors affecting secondary metabolism, sexual development and stress responses in Aspergillus nidulans

et al. 2013

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The eukaryotic basic leucine zipper (bZIP) transcription factors play critical roles in the organismal response to the environment. Recently, a novel YAP-like bZIP, restorer of secondary metabolism A (RsmA), was found in a suppressor screen of an Aspergillus nidulans secondary metabolism (SM) mutant in which overexpression of rsmA was found to partially remediate loss of SM in Velvet Complex mutants. The Velvet Complex is a conserved fungal transcriptional heteromer that couples SM with sexual development in fungi. Here we characterized and contrasted SM in mutants of RsmA and four other A. nidulans bZIP proteins (NapA, ZipA, ZipB and ZipC) with predicted DNA binding motifs similar to RsmA. Only two overexpression mutants exhibited both SM and sexual abnormalities that were noteworthy: OE : : rsmA resulted in a 100-fold increase in sterigmatocystin and a near loss of meiotic spore production. OE : : napA displayed decreased production of sterigmatocystin, emericellin, asperthecin, shamixanthone and epishamixanthone, coupled with a shift from sexual to asexual development. Quantification of bZIP homodimer and heterodimer formation using fluorescence resonance energy transfer (FRET) suggested that these proteins preferentially self-associate.

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Section: Discussionmentioning

confidence: 55%

Section: W-b Yin and Othersmentioning

confidence: 99%

bZIP transcription factors affecting secondary metabolism, sexual development and stress responses in Aspergillus nidulans

et al. 2013

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“…E. festucae YapA functionally complemented the H 2 O 2 stress sensitivity defect of an S. cerevisiae ⌬yap1 mutant and translocated to the nuclei of E. festucae cells in response to H 2 O 2 , properties that demonstrate that YapA is capable of activating genes required for an H 2 O 2 -induced oxidative stress response in S. cerevisiae. However, unlike other filamentous fungi (8,32,33,58), the E. festucae ⌬yapA mutants did not show increased hyphal sensitivity to H 2 O 2 compared to the wild type. Hyphae of the E. festucae ⌬yapA mutants were also resistant to KO 2 and t-BOOH but very sensitive to menadione and slightly sensitive to diamide.…”

Section: Discussionmentioning

confidence: 64%

“…In this pathway, a multistep phosphorelay sensor-responder system transmits the H 2 O 2 oxidative stress signal from the response regulator Mcs4/SskA to the Spc1/SakA MAPK, which phosphorylates and activates the bZIP transcription factor, Atf1/AtfA. Disruption of spc1 and atf1 in S. pombe (61,62) or their homologs, sakA and atfA, in A. nidulans (58,63,64) leads to increased sensitivity to oxidative (H 2 O 2 ) stress. Once again, E. festucae appears to be the exception among the filamentous fungi studied to date.…”

Section: Discussionmentioning

confidence: 99%

“…Introduction of the wild-type yapA gene into the mutant restored H 2 O 2 tolerance of the germinating spores to wild-type levels, confirming a role for YapA signaling in spore adaptation to H 2 O 2 oxidative stress. In A. nidulans, both SakA, through the transcription factor AtfA, and YapA pathways have been shown to be important for conferring spore resistance to H 2 O 2 stress, as both atfA and napA (equivalent to yapA) mutants are sensitive to H 2 O 2 stress (58,64,65). For the SakA pathway, tolerance to oxidative stress is mediated through a spore-specific catalase, CatA, whose expression is regulated by AtfA.…”

Section: Discussionmentioning

confidence: 99%

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Redox Regulation of an AP-1-Like Transcription Factor, YapA, in the Fungal Symbiont Epichloë festucae

Cartwright

Scott

2013

Eukaryot Cell

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One of the central regulators of oxidative stress in Saccharomyces cerevisiae is Yap1, a bZIP transcription factor of the AP-1 family. In unstressed cells, Yap1 is reduced and cytoplasmic, but in response to oxidative stress, it becomes oxidized and accumulates in the nucleus. To date, there have been no reports on the role of AP-1-like transcription factors in symbiotic fungi. An ortholog of Yap1, named YapA, was identified in the genome of the grass symbiont Epichloë festucae and shown to complement an S. cerevisiae ⌬yap1 mutant. Hyphae of the E. festucae ⌬yapA strain were sensitive to menadione and diamide but resistant to H 2 O 2 , KO 2 , and tert-butyl hydroperoxide (t-BOOH). In contrast, conidia of the ⌬yapA strain were very sensitive to H 2 O 2 and failed to germinate. Using a PcatA-eGFP degron-tagged reporter, YapA was shown to be required for expression of a spore-specific catalase gene, catA. Although YapA-EGFP localized to the nucleus in response to host reactive oxygen species during seedling infection, there was no difference in whole-plant and cellular phenotypes of plants infected with the ⌬yapA strain compared to the wild-type strain. Homologs of the S. cerevisiae and Schizosaccharomyces pombe redox-sensing proteins (Gpx3 and Tpx1, respectively) did not act as redox sensors for YapA in E. festucae. In response to oxidative stress, YapA-EGFP localized to the nuclei of E. festucae ⌬gpxC, ⌬tpxA, and ⌬gpxC ⌬tpxA cells to the same degree as that in wild-type cells. These results show that E. festucae has a robust system for countering oxidative stress in culture and in planta but that Gpx3-or Tpx1-like thiol peroxidases are dispensable for activation of YapA.

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The small molecular mass antifungal protein of Penicillium chrysogenum – a mechanism of action oriented review

Hegedűs

Leiter

Kovács

et al. 2011

J. Basic Microbiol.

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The β-lactam producing filamentous fungus Penicillium chrysogenum secretes a 6.25 kDa small molecular mass antifungal protein, PAF, which has a highly stable, compact 3D structure and is effective against a wide spectrum of plant and zoo pathogenic fungi. Its precise physiological functions and mode of action need to be elucidated before considering possible biomedical, agricultural or food technological applications. According to some more recent experimental data, PAF plays an important role in the fine-tuning of conidiogenesis in Penicillium chrysogenum. PAF triggers apoptotic cell death in sensitive fungi, and cell death signaling may be transmitted through two-component systems, heterotrimeric G protein coupled signal transduction and regulatory networks as well as via alteration of the Ca(2+) -homeostasis of the cells. Possible biotechnological applications of PAF are also outlined in the review.

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Characterization of bZip-Type Transcription Factor AtfA with Reference to Stress Responses of Conidia ofAspergillus nidulans

Cited by 66 publications

References 18 publications

bZIP transcription factors affecting secondary metabolism, sexual development and stress responses in Aspergillus nidulans

bZIP transcription factors affecting secondary metabolism, sexual development and stress responses in Aspergillus nidulans

Redox Regulation of an AP-1-Like Transcription Factor, YapA, in the Fungal Symbiont Epichloë festucae

The small molecular mass antifungal protein of Penicillium chrysogenum – a mechanism of action oriented review

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